WASHINGTON - The effectiveness
of the most important U.S. safeguard against mad cow disease was questioned
Monday when a government report accused the Food and Drug Administration
of overstating feed mill compliance with a ban on cattle remains in animal
feed.

The Government Accountability Office report was released
as many U.S. lawmakers seek to prevent Canadian cattle from entering the
United States because of concerns that its neighbor was not effectively
enforcing its own animal feed ban.

In 1997, the United States and Canada both outlawed the
use of cattle remains as a protein supplement for cattle, goats and sheep
to prevent the spread of mad cow disease, a common name for bovine spongiform
encephalopathy, or BSE.

Canada found two more cases of mad cow disease as 2005
began, and both are believed to be a result of infected feed. So far, the
United States has found only one case of mad cow disease, in a Washington
state cow imported from Canada.

The GAO said the FDA, which regulates livestock feed,
cannot pinpoint how many plants comply with the 1997 feed ban.

"We believe FDA is overstating industry's compliance
with the animal feed ban and understating the potential risk of BSE for
U.S. cattle in its reports to Congress and the American people," the
GAO report said.

The FDA has repeatedly claimed that the industry has
a 99 percent compliance rate with the 1997 ban.

Iowa Sen. Tom Harkin, the ranking Democrat on the Senate
Agriculture Committee who requested the GAO report, criticized the FDA
for not testing livestock feed. "Common sense tells us the best way
to measure compliance is to sample feed to make sure it does not contain
ruminant byproducts," Harkin said.